In Islam, it is haram to take pictures of people without their permission. Ideologically, it is tied to frivolous or indulgent pursuits and should not be displayed. So you could take a picture of a significant event to preserve the memory, but it should not be displayed on the wall for others to see. I had to shoot this over the shoulder of another person, because of the people I was with, we were split as to whether or not it was taboo to take a picture of a priest. (Hijab to Wimple to Clerical Collar?) But we could find no reference to anything saying a priest should not have his photo taken, nor a nun for that matter. As a side note, I learned a solid life lesson – don’t google taboo and nun, it’s really disturbing.